Complete Report - University of New South Wales

4.5.3.1.1 TEM of SiQDs in nitride
HRTEM images showing even clearer nanocrystals have been obtained, as shown in Figure
4.5.5.
(a)
(b)
Figure 4.5.5: TEM image of PECVD deposited (a) Si quantum dots in 10 bi-layers of SRN/SiNx
superlattices and (b) HRTEM lattice image.
4.5.3.1.2 TEM Sample Preparation
Transmission Electron Microscopy (TEM) remains a crucial characterisation technique for
nanostructures. TEM sample preparation, however, has traditionally been diffi cult and time
consuming. Great efforts have been made at the Centre to improve the turn around time for
TEM sample preparation. A very promising technique being explored involves a dual beam
Focused Ion Beam (FIB) system. Figure 4.5.6 shows a cross sectional TEM specimen prepared
using a FEI Nova Nanolab 200 Dualbeam FIB, the fl agship instrument at UNSW’s Electron
Microscopy Unit. This same specimen was used to produce the image shown in Figure 4.5.7.
The sample preparation time for this sample was approximately one hour, signifi cantly faster
than traditional techniques.
Figure 4.5.6: TEM Si QD specimen prepared using a dual beam FIB.
Figure 4.5.7: TEM image of Si QDs in a nitride matrix grown by dual-mode PECVD.
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